水工外文翻译渗水根源探究.docxVIP

附录Ⅱ 外文资料及翻译 Straight to the source of seepage Jim Swaisgood, Jerry Montgomery and Val Kofoed report on the investigative work undertaken to discover the source of seepage at River Reservoir dam in the US. Water seeping through an earthen embankment suggests a number of possible circumstances, and none of them are good. At best, the reservoir owner is losing a valuable commodity. The worst case scenario is that the seepage may be the precursor of dam failure. The first step in addressing a problem with seepage is as obvious as it is difficult: pinpointing its source. In the past, procedures for determining the exact location and nature of seepage points have been both costly and time consuming. Of course, when dam failure is imminent, there is much more than money and time at stake; the efficiency and speed with which engineers can locate the source of seepage may make the difference between a timely fix and catastrophe. River Reservoir dam is an arched earthen structure on the headwaters of the Little Colorado River. It is located about 24km southwest of Eagar, Arizona, US, and is owned and operated by Round Valley Water Users Association (RVWUA). Based on very limited engineering, the dam was constructed by settlers in 1896 of local materials and without a clay core. Due to recurring sloughing problems, the dam received significant modifications on at least four separate occasions. The embankment consists of clayey soils within a rockfill shell, measuring 335m long with a maximum height of approximately 21.3m and is founded upon basalt bedrock. In 1996 additional riprap was installed to reduce the original slope of the upstream and downstream faces. A review of the early inspection reports revealed that the left abutment drain was constructed using tabular rocks to create a box-shaped opening over the rock foundation. However, the contacts between these rocks were neither sealed nor grouted. There has been much speculation regarding the original purpose of this dr